Air Exhaust/Ventilation - Veteran growers input please

Well after a smoke break and cleaning the basement up some more I have my final layout. I hope

Equipment
Tent: 48 x48 x 78
Fan: 190 cfm 4"/filter - Air scrubber
Fan: 440 cfm ^" - Air Hood
Speed controller for Scrubber(air hood too maybe, wait and see approach)
May need AC unit.. recording ambient temps now and will cycle the lights for a week and record day/night temps/outdoor temp, but I think I already know I need one



The 6" Intake will be ran 25' into the next room in the basement and the end covered with screen. This room contains an existing 4" dryer style vent. I will replace with a dampener intake vent to replace the outgoing air. The rest of outgoing air (6" vent) will have to pull from somewhere and that will be the from the house, cracks, under basement door, etc. I thought of adding a 6" intake but then id need a heat ex-changer for winter, and thats just too complicated for me The 4" will supply enough fresh air to mix with the ambient temp air and that seems fine to me.

stuckonsticky said:

I built a five by five room eight feet high. .I use a six hundred hps. .I bought a three speed max fan that's 300com..the fan hangs above my light and sucks all the hot air and stick sucks it out six inch ducking through the wall to a fan can filter outside..the filter is a thirty pound carbon filter and you don't smell shit. It was the best addition ever to my garden cuz now the wife will let me do whatever i want.....but one thing ill say its way better to imo suck the air out of the room then to the filter rather than sucking it through the filter then outside...those filters are absolutely amazing...

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Yeah, my last grow was in a 36w x 17d x 78" tall metal storage cabinet. That was about 10 years and one ex-wife ago.. hehe. I stoped the grow during the divorce for obvious reasons. I recently had to wait like 3 weeks for my guy to hook me up and that was the last straw. I re-assembled my box and after a 24hr cycle with temps reaching 100 plus degrees with venting I needed a new solution.

My house use to reeeek to high hell. I could smell it from the yard outside the house before. I just vented with a 10.00 box fan jerry rigged to the side of the cabinent and vents cut into the sides. Ok yields of maybe 2-3 ounces, but I am sure the temps were as high before and severely affected my yields, not to mention the extra water the plants need in higher temps just stresses them out even more I imagine.

This time I want it to be a perfect summer day in that tent, 75 deg and sunny with relative humidity, you know grab a chair, a drink and just take in the beauty type of day.

Imo this ways best....i don't have to vent shit..it just goes into my cellar..not that your set up is like mine but i thought it may help to see others set ups.

Thanks,

After a long deliberation I have decided to go with my final design posted above. 6" 440 CFM pulling air from the next room in the basement 25' away through the hood and out the basement window. 4" 190 cfm fan / filter to create negative pressure and pull air passively through the bottom vents.

I have installed the 6" and 4" outlet vents and will install the fans in a few days when the arrive. Eventually I will add a 6" intake to supply fresh air, but I have an existing 4" vent I will convert for now.

I will not connect the 6" tube intake for the hood to the outside vent letting fresh air in. I will simply have the draw tube hanging in the same room passively pulling in fresh air which will allow it to mix with the ambient temp air before being drawn into the grow by the 4" fan/filter.

This will cool my hood, exhaust stale air, and replace with fresh. Win, win, win. Now I need some grow, grow, grow.

Thanks all

shouldnt the filter be on the other side of the hood? in between the hood and fan.

crazar said:

shouldnt the filter be on the other side of the hood? in between the hood and fan.

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You can set it up that way to vent the grow and the hood all in one. Use a 6" 440 cfm fan/filter.

I am thinking about summer heat and higher temps. I want complete control over the temperature and venting both the hood and the grow separately offer me peace of mind. I will have speed controllers on both fans to dial them in for summer or winter. Faster in the summer, slower in the winter.

This will allow me to have a temperature switch on the fan for the grow. That way if the lights are off and temps start to rise the fan can vent the grow independently from the lights/hood exhaust.

i was thinkin.. if u put the filter on the other side. u will pull the air through the hood and then filter instead of having.. air going through the filter and some air going through the hood.

I'm currently using a 300CFM fan and still have some trouble cooling my 600W air-cooled reflector efficiently. Definitely go with the 440CFM, you won't regret it.

im not fond of passive intakes myself. I think your fans are going to be working really fuckin hard. You will no doubt get a negative pressure but i would look into another fan feeding the intake on your hood exhaust and pull that air from outside the house while the lights run at night

I think you might be more efficient if you place the 6" fan before the light so that the cool air is blowing over the light and not sucking the hot air over it. I believe this will significantly help with the longevity of the equipment. Also I might suggest moving the fan for the exhaust closer to the filter because in my tent I originally had it where you do and it was still very loud outside of the window. Also I believe it is more efficient at scrubbing because it pulls more air pressure evenly across the hole filter. I have been experimenting in my op with the same thing and I believe your design is going to work well for you. I am now able to control temps to 2 degrees over ambient room temp.
Happy Growing
KnB

Also you might look into going to the hardware store and buying a fan motor controlling switch, sometimes it's cheaper than the speedster with more control but YMMV.

Paperhouse said:

I'm currently using a 300CFM fan and still have some trouble cooling my 600W air-cooled reflector efficiently. Definitely go with the 440CFM, you won't regret it.

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Yeah, I have ambient temps of 80 degrees with no equipment running so I figure 6" 440 for the hood only, and a seperate 4" 190cfm for the exhaust. I have installed a 4" & 6" Vents to exhaust both outside.

im not fond of passive intakes myself. I think your fans are going to be working really fuckin hard. You will no doubt get a negative pressure but i would look into another fan feeding the intake on your hood exhaust and pull that air from outside the house while the lights run at night

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The air in the basement is about 12-15 degrees cooler than the outside air. I have been monitoring for about 3 weeks now. I have another 6" 240 cfm duct fan for feeding the intake if needed, but will wait and see after testing the setup with some bagseed

Thanks guys for all your invaluable input ! I would have had a shitty super hot sweat box tent for my babies without your knowledge and advise. I will post some pics once it is all set up and running!

silentmercy said:

Thanks guys for all your invaluable input !

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Thats why we're here at RIU.

Good luck and make sure you test with everything ON for at least a full 24hour cycle so you know HI's and LO's of temp and RH.



J

jondamon said:

Thats why we're here at RIU.

Good luck and make sure you test with everything ON for at least a full 24hour cycle so you know HI's and LO's of temp and RH.
J

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Thanks, Jondamon! Exactly my thoughts. I want a good 24-48 hour test run because if temps/humidity are too high I was thinking about installing a 6" intake for the hood. Pull the air from outside, through the hood, and outside the opposite wall in the basement to avoid re-circulation of the same air.

I would like to know your thoughts on this. Are you bringing in fresh air from outside or just pulling from the attic through the hood and back into the attic?

kushnotbush said:

I think you might be more efficient if you place the 6" fan before the light so that the cool air is blowing over the light and not sucking the hot air over it. I believe this will significantly help with the longevity of the equipment. Also I might suggest moving the fan for the exhaust closer to the filter because in my tent I originally had it where you do and it was still very loud outside of the window. Also I believe it is more efficient at scrubbing because it pulls more air pressure evenly across the hole filter. I have been experimenting in my op with the same thing and I believe your design is going to work well for you. I am now able to control temps to 2 degrees over ambient room temp.
Happy Growing
KnB

Also you might look into going to the hardware store and buying a fan motor controlling switch, sometimes it's cheaper than the speedster with more control but YMMV.

Click to expand...

Glad to hear about your success brother, uplifts my spirits... Im obsessing over the exhaust set up I was going to mount the fans to the board on the window but have since opted to mount to the floor joist with rubber bushings. I was worried about the vibrations and sound too.

I have not received the tent or the 6" fan yet so I still cannot start testing, but the 4" fan will be only 3-4 feet from the filter with no bends... just a straight shot... the total length of the run from the filter to the exit out of the basement will be only 12 feet at most.

So were your temps higher pulling the air through the hood and they lowered when you put the fan on the other side blowing ?

If you check my closet build, on the left side of the closet in the ceiling i have 2x5inch ducting and 1x6inch ducting pieces, they are all tucked into my soffit vents pulling cool air from outside, the 2x5inch ducting pieces are just passive vents, the 1x6inch is the cool feed for the hood, The hood exhausts into my main attic area along with the 2nd fan attached to the filter, i added EXTRA ventilation to my attic to create cross flow in there to keep the whole area cool.


J

jondamon said:

If you check my closet build, on the left side of the closet in the ceiling i have 2x5inch ducting and 1x6inch ducting pieces, they are all tucked into my soffit vents pulling cool air from outside, the 2x5inch ducting pieces are just passive vents, the 1x6inch is the cool feed for the hood, The hood exhausts into my main attic area along with the 2nd fan attached to the filter, i added EXTRA ventilation to my attic to create cross flow in there to keep the whole area cool.


J

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Ok, got it. When your filter kicks on your exhausting the stale air and passively pulling in fresh air from outside with the 2-5" vents.

If your pulling fresh air passively into the garden, what about freezing temperatures? It will be quite cold where I am in a few months

I am sure you have a damper, but I am curious about the cold air and the plants or is it not an issue since the exhaust does not run that much during colder times?

I am not in the same exact situation as you(no two people really ever are I guess) but I obsessed over my exhaust for weeks!!!! In fact, I set it up and tested it more times then I can remember. The thing is that there was always another factor that I didnt account for, even though I did copious amounts of research. If you have that low of outside temps, I would use this. I have this(link) model from this site and I love it sooo much. I dont have to worry about anything. Be careful about using fan speed adjustments, on cheaper fans, that arent made to be adjusted, it can burn them out really fast

chasmtz said:

I am not in the same exact situation as you(no two people really ever are I guess) but I obsessed over my exhaust for weeks!!!! In fact, I set it up and tested it more times then I can remember. The thing is that there was always another factor that I didnt account for, even though I did copious amounts of research. If you have that low of outside temps, I would use this. I have this(link) model from this site and I love it sooo much. I dont have to worry about anything. Be careful about using fan speed adjustments, on cheaper fans, that arent made to be adjusted, it can burn them out really fast

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Hehe, we think alike! Actually I was going to opt for LINK HERE Cap 4 Controller as it has everything I will eventually need or " grow into" pun intended ! The individual controllers are about 65.00 - 85.00 U.S. this one is $160.00 and has Temp, humidity, night, Co2 controllers. I deem it to be the better value as eventually I may add Co2, or will need a night controller along with temp !

Thanks for the tip on the fans, mine just arrived today. One is a Vortex brand so probably no worries there, but the other is not. Was supposed to be Vortex, looks the same, but no Vortex sticker on fan. I will hope they both last!